Opioid use in pregnancy doubled between 1998 and 2011. Neonatal abstinence syndrome (NAS) occurs in newborns exposed to opioids in-utero. Opioids delay gastric emptying and inhibit gastric motility in adults, however, it is unknown if opioids affect the fetal gastrointestinal system. We assessed whether gastric size in opioid-exposed fetuses predicts NAS treatment.METHODS:
We undertook a retrospective cohort study of maternal-neonatal dyads with chronic opioid use who delivered at our tertiary hospital January 2005 to April 2017. Primary outcome: treatment for NAS (3 consecutive Finnegan scores >8 or 3 scores >24 within 96 hours of life). Medical records were reviewed for maternal and neonatal demographics and fetal ultrasound images. Fetal gastric size was measured from abdominal circumference images using major and minor axis calculating an ellipse comparing this to the abdominal circumference to derive the gastric area ratio (GAR). Analysis was two-sided (alpha of 0.05) by t-test for continuous and chi square for categorical variables.RESULTS:
We identified 49 maternal-neonatal dyads. NAS treatment occurred in 67% (n=33) of neonates. Neonatal length of stay was longer [26.9 (days) ± 13.7 vs 8.2 ± 7.7, p<0.001] and mean peak Finnegan scores were higher in infants treated for NAS (12 ± 3 vs 5 ± 3, p<0.001). GAR was not different between groups [2.91 ± 1.5 (treatment) vs 2.85 ± 1.6 (no treatment), p=0.90] and did not predict NAS treatment.CONCLUSION:
Fetal GAR does not predict NAS treatment. More studies are needed to determine if an ultrasound marker predictive of NAS treatment exists.